World crude prices have risen amid fears that supplies from the oil-rich Gulf of Mexico could be disrupted by Hurricane Ivan.

Energy companies have evacuated thousands of offshore workers and shut down some production in the region.

Prices were also pushed higher on Tuesday by news of an attack on a oil pipeline in northern Iraq.

US light crude closed Tuesday trading up 52 cents at $44.39 a barrel while London Brent rose 81 cents to $41.87.

Supply worries

Hurricane Ivan, which is one of the fiercest Atlantic storms on record, was heading into the Gulf of Mexico on Tuesday after leaving a trail of destruction across the Caribbean islands.

The Gulf of Mexico is home to around one quarter of US oil and gas production.

Anglo-Dutch oil group Shell said it had halted 272,000 barrels per day (bpd) of oil output in the region, while US rivals ChevronTexaco, ExxonMobil and French oil giant Total also said they were also shutting off some production and evacuating offshore workers.

Although Hurricane Ivan is not expected to hit the bulk of production in the Gulf of Mexico, low stocks of fuel in the US have left traders nervous at the prospect of any disruption to the supply chain.

Opec gathering

Oil markets were also shaken by an attack on an oil pipeline in Iraq on Tuesday. The pipeline was blown up, halting more than 200,000 bpd of crude exports from the oilfields of northern Kirkuk to the Turkish Mediterranean port of Ceyhan.

The oil was being pumped into Turkey through a back-up pipeline following an attack on Iraq's main northern export pipeline at the beginning of September.

News of the latest attack came as ministers from oil producers' cartel Opec gathered in Vienna ahead of a meeting on Wednesday.

Key exporter Saudi Arabia said on Tuesday that it was keen to push crude prices below $40 a barrel, and would maintain output at 9.5 million bpd in October in an attempt to cool the market.

Opec ministers are not expected to announce any major changes to their production quotas.

Separately, China's state media said oil imports for the first eight months of 2004 rose by nearly 40%, compared with the same period last year.

China imported a total of 79.9 million tonnes of oil between January and August, reflecting a slowdown in domestic oil production at a time of rapid economic expansion.